Question

What is the mass of 56 cm 3 of carbon monoxide at STP?

Answer 1

56 cm^3 = 0.056 L

At STP
Volume of 28g of CO is 22.4 L
Mass of 0.056 L of CO will be = (0.056 * 28) / 22.4
= 0.07 g
= 70 mg

Mass of 56 cm^3 of carbon monoxide is 70 mg

Answer 2

Molecular mass of CO = 12+16

=28

so, 56cm3 =0.056 litre

therefore,

mass of 0.056 litre of CO = 0.056*28/22.4

=0.07 g

= 70 mg